Polyvinyl acetal resin sheet containing tripropionin



Patented Dec. 5, 1939 UNITED STATES POLYVINYL ACETAL RESIN SHEET CONTAINING TRIPROPIONIN Emmett K. Carver and Bruce E.- Gramkee, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application December '15, 1937,

SeriaiNo. 179,962

Claims.

' This invention relates to plastic compositions and more particularly to compositions comprising a polyvinyl acetal resin and a conditioning agent. u g

One object of this invention is'to produce compositions of matter which 'may be made into permanently transparent, strong and flexible sheets or films of desired thinness which are substantially waterproof, are unafiected by ordi- .0 nary photographic fluids and possess the desired properties of a support for sensitive photographic coatings. Another object of our inventionis to produce compositions of matter which can be made into'sheets suitable for use in laminated, i5 shatter-proof glass. Still another object is to produce compositions which can be rolled,'ex'- truded, 'molded or otherwise worked into relatively thick sheets and massive plastics. A further object is to produce compositions suitable. go for use in lacquers, artificial silk filaments, wrapping tissues and the like. Other objects will hereinafter appear.

We have discovered that tripropionin, i. e., glycerol tripropionate, is an extremely useful 35 conditioning agent for polyvinyl acetal resins.

Not only does it serve as a plasticizer in the accepted sense of the term, increasing the flexibflity and toughness of polyvinyl acetal resin films, sheets, or other objects or masses containing it, 30 but when used in amounts of about 40 or 50 or more parts per 100 parts of the resin, it has an unusual and remarkable effect which-we may call elasticizing. That is to say, a sheet of polyvinyl acetal resin containing, about 40 or 5 more parts of tripropionin per 100 parts of resin possesses the property which, in the rubber industry, is known as nerve: namely, the prop- ,erty ofstretching to aconsiderable extent when tension is exerted upon it, and returning toits m original dimensions when the tension is released. This property renders such sheets, which we shall call rubbery sheets, particularly useful in the manufacture of shatter-proof glass.

For the manufacture of cast films or sheets, the polyvinyl acetal resin and tripropionin may be dissolved ina suitable solvent or solvent mix ,ture, such, for instance, as acetone, methanol, -acetone-methanol mixtures, ethylene chloridemethanol mixtures, etc., about 300 to 500 or more parts of the solvent or solvent mixture being used per 100 parts of the resin. From about 5 to 100 parts or more of tripropionin per 100 partsof resin may be employed, depending upon the nature of the resin and the purpose for which 55 the sheets are to be used. Suitable proportions of tripropionin for any resin and any purpose may be readily determined by experiment. For

the manufacture of sheets suitable for photographic film base, from 3 to 25 parts of tripropionin per 100 parts of resin are suitable. The resin solution is cast as a sheet, solvent evaporated, and stripped from casting surface.

Sheets for use in laminated glass may be formed by casting, or may be made without the use of volatile solvent by extrusion. for example, in the manner set forth inapplication Serial No. 147,934 of John S. Kimble and Ernest C.

' Blackard, filed June 12, 1937. For instance, 40 or more parts of tripropionin and 100 parts of a polyvinyl acetal resin may be mixed in a suitable jacketed mixer at a low temperature, for example 10 0., and the mixture may then be worked on hot rolls, in the manner described in United States Patent 2,048,686 of F. R. Conklin, until complete homogenization has taken 'place. The mass thus produced may then be extruded through an annular die, and the tube so formed slit to form a sheet. When the resin used is a polyvinyl formaldehyde acetal resin, it will usually be found necessary to'use 60 or more parts of tripropionin per 100 parts of resin. The use of a reduced temperature in the preliminary mixing is expedient because tripropionin is a solvent or swelling agent for the polyvinyl acetal resins at room temperature.

The polyvinyl acetal resins can be prepared by reacting polyvinyl alcohol with an aldehyde in the presence of an acetal condensation catalyst, e. g., a mineral acid. These resins can also be prepared by simultaneously de-esterifying a polyvinyl aliphatic ester and reacting the deesteriflcation .product with an aldehyde in the presence of a de-esterifyinig catalystandacetal condensation catalyst. Mineral acids are catalysts for both tie-esteriflcation and acetal formation. Among the polyvinyl acetal resins with which tripropionin is useful may be mentioned, as illustrative examples, the polyvinyl formaldehyde acetal resins, the polyvinyl acetaldehyde acetal resins, the polyvinyl formaldehyde acetaldehyde mixed acetal resins, the polyvinyl butyraldehyde acetal resins, and the polyvinyl butyraldehyde acetaldehydemixed acetal resins.

Examples of the preparation of polyvinyl formaldehyde acetal resins may be found in United States Patent 1,955,068, Examples-1, 4 and 5; in United States Patent 2,036,092, Exam- 'ples l, 2, 3,7 and 8; in British Patent 454,691, Examples 1, 2, 3, 4, 5,6 and 7; in British Patent 404,279, Example 3; andin British Patent 436,072,

.C., after which. it W Examples 1, z,- s, 4', s, a and '1. Further examples of the preparation of polyvinyl formaldehyde resins are as follows: lbs. of polyvinyl acetate. the viscosity of whose molar" solu tion (86.08 g. per liter) in "benzene was 45 centipoises, was dissolved m'vs droxyl group content equivalent to 7.1%"by weight of polyvinyl alcohol. The stabilization of polyvinyl acetal resins by hydroxylamine'is claimed inthe application of Joseph B.Hale, Serial"No;. 149,916, vfilled June 23. 1937, now Patent No. 2,146,735. r a

70 lbs. of polyvinyl acetate. the viscosity of whose, molar solution in benzene was 45 centipoises, was dissolved in a mixture of 336 lbs. of glacial acetic acid and 224 lbs. of water. After solution was eifected, there were added a solu-' tion of 318 grams of sodiumnitritej in 500 cc. of water; for stabilizing the resin, 15.2- lbs. of trioxymethylene'and 17.5 lbs. of 35% 1101. The reaction mixture was allowed "to stand for 5 days at 40- 0., whereupon 5 lbs.- additional 35% H01 was added and the reaction continued for 6 days longer: a total of 11 days at140 0.1 The reaction mixture was then diluted with a mix ture of acetic acid and ethyl alcohol, and the resin wasprecipitated by pouring into-cold water, washed, and dried. Analysis showed the resin to have an acetate group'content equivalent. to 10.7% by weight'of polyvinyl acetate and a hydroxyl-group content equivalent. to 11.2% by weight of-polyvinyl alcohol. The stabilization of polyvinyl acetal resins by nitrous acid is claimed in the application of Charles B. Fordyce and Martti Sale, Serial No. 159,193, flied August 14, 1937, now Patent. No; 2,159,263. 1'

Examples of the preparation of polyviny acetaldehyde acetal resins .may be found in United States Patent 2,044,730, Example. 1; United States Patent 1,955,068. Example 2; United States Patent 2,036,092, Examples 4. 5 and'6; British Patent 466,598, Examples 1, 2, 3, 4 and 7; British Patent 404,279, Examples 1 2, 4, 5, 6, 7 and 8: United States Patent 1,990,399; and French Patent 808,578. Examples l, 2 and 3.

Additional examples of the preparationof poly- .vinyl acetaldehyde acetal resins are as follows;

100 lbs. of'polyvinyl acetate. the viscomty of whose molar solution in benzene was 45 centimixture was allowed to stand for 4days at'40 0.,

noises. was dissolved in 300 lbs. of 95% ethyl'aicohol. To this solutionwas added lbs. of paraldehyde and 25 lbs. of H01. The reaction,

after which it was diluted with ethyl alcohol, and the resin precipitated by pouringinto cold water, washed and dried. Analysis showed the resin '-to have an acetate group content equivalent 'to 2.1% .by weight of polyvinyl acetate and, a hydroxyl group content equivalent. to 12.9% by weight of polyvinyl alcohol. a

25 lbs. of polyvinyl acetate, the viscosity of.

. whosemolar solution in benzene was '45 centipoises, was dissolved in 75 lbs. of. 95% ethyl alcohol.

To this solution was added 8 lbs. of par aldehyde anda solution of 3 lbs. 12 ozs. of sulfuric acid in 3 lbs. 12 cos. of 95% ethyl alcohol. The reaction mixture was allowed to stand for 7 days at 0., after which. it was diluted with ethyl alcohol, and the resin precipitated by pouring into cold water, washed, and dried. Analysis 5 showed the resin to have an acetate 8113 content equivalent to 1.7% by weight of polyvinyl acetate and a hydroxyl group content equivalent. to 13.8% by weight of polyvinyl alcohol.

Examples of the preparation of polyvinyl formaldehyde acetaldehyde mixed acetal resins may be found'in British Patent 430,136, Examples 1, 2, 3, 4, 5 and 6; British Patent 445,565, Example 2; British- Patent 465,873, Examples 1, 2,

, 3, 4, 5 and 6; French Patent 808,586, Examples 15 1,2, 3, 4, 5, .6, 12, 13, 14, 15, 16,17, 18 and19. Additional examples of the preparation of polyvinyl formaldehyde acetaldehyde mixed acetal resins are given in the, application of Ralph H. Talbot, Serial No. 85,960,1iledfJune18,

1936, as follows:

' Emmplel The contents of the vessel were then diluted with about two and a half volumes of acetone, and the mixture precipitated into water. The. pre cipitated resin was washed freefrom impurities by repeated changes of'cold water, and dried-.-' The resin, when analyzed, gave a hydroxyl group content equivalent to about 6.4 percent by weight of polyvinyl alcohol, an acetate group content equivalent to about 4.0 percent'by weight of polyvinyl acetate, a formaldehyde acetal group content equivalent to about 15.9 percent by Y weight of polyvinyl formaldehyde acetal and an acetaldehyde acetal group content equivalent to about 73.9 percent by weight of polyvinyl acetaldehyde acetal. The polyvinyl acetal portion of the resin was therefore made 'up' of about 19.7 percent 'by moles of polyvinyl formaldehyde acetal and about 80.3 percent by moles of'poly- I vinyl acetaldehyde acetal. The resin was soluble in acetoneto an extent which permitted coating a dimer sheet from the resin.

"50 parts (.58 mol. as monomer) of polyvinyl acetate centipoises). parts of ethyl alcohol, .90 partsof ethyl acetate, 17 parts. (.385 moL'as monomer) of par-acetaldehyde, 2.9 parts (.098- mol. as'monomer) of'paraformaidehyde, 5 parts 2 ofsuifuricacidand5partsofwaterweretreated' acetate, a formaldehyde acetal fgroup oontent ioequivalentto about 13.9 percent .byweight of polyvinyl formaldehyde-acetal, and an acetaldehyde acetal group content equivalent to about 69.9 percent of polyvinyl acetaldehyde acetal.

The polyvinyl acetal portion of the'resin was.

therefore, made up of about 18.5 percent by and repeatedly washed with hot water u n ises, was dissolved in acetal. The extent which permitted coating a film or sheet tone, but could be made to moles of polyvinyl formaldehyde acetal and 81.5 percent by moles of polyvinyl acetaldehyde resin was soluble in acetone to an from the resin.

"Example 3 a 1300 parts (15.1 mol. as monomer) of a polyvinyl acetate (45 centipoises) 1700 parts of ethyl acetate,.2250 parts of ethyl alcohol (95%) and 48 parts (1.57 mol..as monbmer) of paraformaldehyde (trioxymethylene) were placed in a vessel equipped with a refluxcondenser and a means of agitation, and the contents brought to a temperature of about C. by means oi steam heating., 182.25 parts of sulfuric acid (sp. g. 1.84)

-..dissolved in 51.5 parts of water were added, and

the whole was heated at about 70 C. for about five hours, agitating throughout.- At this point, 266.4 parts (6.05 mol. as monomer) of paracetaldehyde were added and heating at about 70 C. a

with agitation was continued for a further period of twenty hours. The contents of the reaction vessel were neutralized with ammonium hydroxide'and diluted with waterprecipitating the resin as a cake. The cake was cut into small pieces until the resin was free from solvents, salts and other impurities. The resin, upon analysis, showed a hydroxyl group content equivalent to about 10.1 per cent by weight of polyvinyl alcohol, an acetate group content equivalent-to about 3.2 percent by weight of polyvinyl acetate, the, re

mainder of the weight of theresin being polyvinyl acetal. The polyvinyl acetal portion of the resin was made up of about percent by moles of polyvinyl acetaldehyde acetal and about 20 per cent by moles of polyvinyl .formaldehyde acetal. The resin was not quite soluble in acedissolve by admixing small amounts of other solvents, such .as alcohols, with the acetone.

1101 and 36 lbs. of ethyl acetate. To. this solution was added 13 lbs. of butyraldehyde and a solution of 2 lbs. of sulfuric acid in 2 lbs. of water; The reaction mixture was allowed to stand for 8 daysl-at 40 C., after whichv it was diluted with acetone, and the resin precipitated by pouring into cold water, .washed and dried. showed the resin to have an acetate group content equivalent to 7.8% by weight of polyvinyl acetate and a hydroxyl group content equivalent to 4.8% by weight of polyvinyl alcohol. 23.6 lbs. of polyvinyl acetate, the viscosity of whose molar solution in benzene was 45 centipoises, was dissolved in 56.5 lbs. of ethyl alcohol. To this solution was added 7.9 lbs. of

Analysis butyraldehyde and 5.9 lbs. of 35% HCl. The reaction mixture was allowed to stand for 4 days ,at 40 0., after which it was diluted with ethyl alcohol and acetic acid, and the resin precipitated by pouring into cold water. washed, and dried. Analysis showed the resin to have an acetate group content equivalent to 3.1% by weight of polyvinyl acetate and a hydroxyl group con- :tent equivalent to 16.3% by weight of polyvinyl alcohol. v 2

An example of the preparation of a polyvinyl butyraldehyde acetaldehyde mixed acetal resin is given in Fi'ench Patent 813,303, Example 2.

What we claim be secured by Letters Patent of the United States is:

l. A transparent, rubbery'sheet comprising parts-of a polyvinyl acetal resin and at least 40 parts, approximately, of tripropionin as an elasticizer therefor.

2. A transparent, rubbery sheet comprising 100 parts of. a polyvinyl acetaldehyde acetal resin and at least40 parts, approximately, of. triproplonin as an elasticizer therefor- 3. A transparent, rubbery sheet comprising 100 partsof a polyvinyl formaldehyde acetal resin and at least-60 parts, approximately, of tripropionin as an elasticizerthereior. a

4. A transparent, rubbery sheet comprising 100 parts of a polyvinyl butyraidehyde acetal resin and at least 40 parts, approximately, of tripropionin as an elasticizer'therefor.

5. A transparent,

polyvinyl acetal r triand an amount of propionin suillcient-to impart to the sheet a rubbery character without substantially impairing its transparency.

WIT K. CARVER. BRUCE E. GRAMKEE.

as our invention and desire tov rubbery sheet comprising a- 

